Germanium(IV) iodide is an inorganic compound with the chemical formula GeI<sub>4</sub>.
Germanium(IV) iodide can be obtained by the reaction of germanium and iodine or the reaction of germanium dioxide and 57% hydriodic acid:
Germanium(IV) iodide reacts with tetraalkyl tin at 250 ðC to form R<sub>2</sub>SnI<sub>2</sub> and R<sub>2</sub>GeI<sub>2</sub> (R= Et, Bu, Ph). It reacts with germanium and sulfur at high temperatures to produce red GeSI<sub>2</sub> and orange Ge<sub>2</sub>S<sub>3</sub>I<sub>2</sub>. It reacts with diiron nonacarbonyl in an ionic liquid ([BMIm]Cl/AlCl<sub>3</sub>) at 130 ðC to obtain Ge<sub>12</sub>[Fe(CO)<sub>3</sub>]<sub>8</sub>I<sub>4</sub>.
Germanium(IV) iodide is an orange-red crystalline solid that hydrolyzes in water. It is soluble in carbon disulfide and benzene, but less soluble in carbon tetrachloride and chloroform. It begins to decompose into germanium(II) iodide and iodine above its melting point. Germanium(IV) iodide crystallizes in the cubic crystal system, space group Pa (space group no. 205), with the lattice parameter a = 11.89 ÃÂ . The crystal structure consists of tetrahedral GeI<sub>4</sub> molecules.